I just bought this version of this game today and tried it out with the Wii U gamepad with TV off. After playing a few matches, I noticed there's something not right with the audio.

The issue is that I hear gun fire and explosions from the right speaker when it's ACTUALLY coming from the left side, and vice versa. The audio's left and right speakers are flipped. I looked in the audio options, and there's no way to fix this unless I wear headphones (Specifically ear buds).

I think you're missing the point here. He shouldn't have to look for an alternative. The left and right speakers should be outputting the correct channels. If they're not it needs to be looked into and not be given workarounds.

I'm not missing anything. Heaphones were suggested because the gamepad speakers are, well, not the best. He said it wasn't worth it so I suggested some cheap alternatives that he may or may not have considered. He probably has, but I don't like to assume things.

if you set the console to surround it cuts half the sound out of zombiu...oh you didn't know lol. When the console is set to surround you have to run it through a receiver to get surround, I blame nintendo/nt!